Sulphurized cinchona bark inhibitor



Patented July 12, 1932 UNITED STATES PATENT OFFICE GEORGE LUTZ, OF ROCKY RIVER, OHIO, ASSIGNOR TO THE GRASSELLI CHEMICAL COM- PANY, OF CLEVELAND, OHIO, A CORPORATION OF SULPHUBIZED CINCHONA BARK INHIBITOR Io Drawing. Application filed December 16, 1931. Serial No. 581,518.

This invention relates to processes of cleanfluid. A definite amount of powdered suling and pickling metal articles by the action phur is then stirred into the molten mass of acids thereon, and is particularly directed with continued heating until a sudden rise in to the use in cleaning and pickling baths of temperature is noted, at which point the heatcertain organic substances which I have ing is discontinued. The sudden rise in temfound to have the property of inhibiting the perature is accompanied by vi orous reaction action of acids upon the metal itself, withwith copious evolution of H and the mass out in any substantial manner hindering its is stirred constantly to prevent excess foamaction on the oxide, rust and scale or other ing. The sudden rise in temperature brin s In undesirable incrustations which such operathe temperature up to 135 G.140 C.,andt e tions are intended to remove from the metal. massis kept at this temperature for at least I have found that sulphur or substances minutes before cooling. 7 which release sulphur on heating in contact The amount of sulphur used in preparing with nitrogenous organic substances will rethesesulphurizedcompounds may vary from 15 act with cinchona bark alkaloids to form new ,5-' by welght, although in my presubstances which, in the absence of a more ferred Process I P about y Welghtthorough understanding of the chemical re- These sulphun?ed mp un y a1S0 be actions involved, I shall designate as sulfi g by heatlilg qlimoldme or the Phurized cinchona bark alkaloids Typical c ona ark alkaloids with sulphur chloride 0 representatives of the cinchona b instead of powdered sulphur, either direct or has g gi fiza 51 53 2: gi l fiig gii% ization processes are substantially the same in properties. They vary in the amount of fifihdlnal alkaloids from the cinchona bark. sulphur combined according to the amount I further found that these novel, sulphurof sulphur or sulphurization reagent used, ized alkaloids act as inhibitors in cleaning and are probably mixtures of various suloperations lIlVOlVlllg the action Of IlOIl-OXld hurized products and contain anywhere ing acids upon metal articles. roin 5 to 15% S.

80 My invention comprises these novel sul- They are yellowish to reddish-brown,britphurized cinchona bark alkaloids and their tle masses which are easily ground to powder. application to the control of the action of Th y ha n d fi it l known h i l acids upon metals.

composition, though from analogy with the My novel sulphurized compounds are presulphurization of aromatic amines, it can be pared by heating the alkaloids with elemental a um d that th ul h enters b l sulphur, sulphur chloride or other substances ment of hydrogeninto the nuclei of the alwhich release sulphur on heating, either dikaloids. rect or in the presence of a catalyst, such as These sulphurized alkaloids have no defialuminum chloride. nite melting point, they melt between about Apreferred process for preparing sulphur- 135 to 200 0., that is to say, higher than ized quinoidine or sulphurized cinchona bark the raw materials. alkaloids is as follows: They are insoluble in aqueous caustic al- The quinoidine or cinchona bark alkaloid is kalis and difiicultly soluble in the common orfirst melted in any suitable receptacle until ganic solvents, except in chloroform.

They are almost completely soluble in dilute mineral acids, seemingly without decomposition, even on boiling.

The main use I found for these novel substances is in metal cleaning operations.

The use of cinchona bark alkaloids as inhibitors is disclosed in U. S. Patent No. 1,742 986 Jan. 7, 1930, H. P. Corson, inhibiqfto rf lhave ioundthat my novel sulphurized cinchona bark alkaloids present certain advantages over the original alkaloids in metal cleaning operations in that the new derivatives are easier soluble in the cleaning acid solution and have a higher pickling eificiency.

Pickling and metal cleaning operations involve commonly the use of dilute non-oxidizing acids, such as'siilpliuric, hydrlichloric, acetic, formic, aqueous solutions of acid sulphates, etcifand such baths are used for numerous purposes, of which pickling in steel mills is the most typical representative. The composition, concentration, temperature and other factors vary with difierent baths, but the underlying principle comprises in all cases the removal of undesirable incrustations by the action of the acid. The bare metal so obtained is then in the absence of an inhibitor unavoidably subjected to attack by the acid with unnecessary loss of metal, weakening of the article and unnecessary consumption of acid.

My novel inhibitors, comprising sulphurized quinoidine and other sulphurized cinchona bark alkaloids are efficient inhibitors with the various commonl used ickling and cleaning acids. Ihe application in'y'in vention to acid pickling and acid metal cleaning operations does not involve any change in the baths and operation thereof, except for the addition of a small amount of these inhibitors. Less than A; of 1% of sulphurized quinoidine added to an acid pickling or cleaning bath will, to a large extent, if not entirely, prevent the attack of the base metal under the conditions where all undesirable incrustations are removed. In some instances amounts of 1% or less are efiicient and sufiicient for all purposes.

In pickling operations the concentration of acid in the pickling bath varies from to and the temperature from 140 to 190 F. Laboratory tests by the so-called loss in weight method which consists of a beakerj scale pickling operation using a 6% sulphuric acid pickling bath, at 180 F.. noting the loss in weight of the steel after onehalf hour, and after two one-hour periods of immersion after the first half hour immersion in the bath, showed my novel inhibitors to have the following inhibiting efficiencies when the sulphurized products are compounded at the rate of 10% with 90% inert ingredients:

Concentration of compounded inhibitor 1% Period of pickling 1 2 8 1 2 3 Time of ickling (minutes).. 30 60 Scale inc uded. Yes. No. No. Yes. No. No

Active ingredient composition Quinoidine, Reacted with sulphur,

85 15 72. 5 92. 4 82. 6 76.2 97. 7 97. 5 80 20 64. 9 90. 4 80.2 77. 4 9a. 0 9S. 0 85 15% sulphur TI. 6 88. 9 7T. 3 79. 1 97. 7 9T. 3

chloride. 100 None. 829 34.6 88.9 44.6

Cmchonine Reacted with oid, sulphur,

90 81.7 78.2 63.5 81.6 97.04 96.1 100 None. 40.6 61.9 429 In the above table the efiiciency for the first period includes the loss in weight due to adering scale and other incrustations, which varies on the different specimens of steel. In the second and third periods the loss is due to loss of bare metal only.

Four inhibited acids were prepared by dissolving sulphurized quinoidine in cold 18 B. commercial muriatic acid at the rate of 1%, .5%, .1% and 02%.

Portions of these acids were then diluted to 15% acidity as HCl and the inhibiting efficiency was determined on 26 gauge black sheet steel at 8090 F.

The first period of pickling consists of 5 hours during which the scale was removed, and the second period of pickling consisted of 16 hours after the first 5 hours, The loss in weight of the steel was noted for each eriod and calculated to per cent inhibitlng efiiciency.

Results obtained Inhibiting eflfieiency of 18 B. commercial murlatic acid containing 1 5%, .1% and .02% sulphurized quinoidine diluted to 15% acidity at 80-90" F. on 26 gauge black sheet steel I 1st Peri-0d l' gifi iig 21 hours Concentration of sulphurized fig 16 hours ickling quinoidine in 18" Be. H01 ap r first oalies ours is e included no scale Similar efiiciency figures were obtained with quinine and quinidine sulphurized with 5, 10, 15 or 20% sulphur without or with for instance 2% aluminum chloride.

I claim:

1. A cleaning and pickling bath for metals comprising a dilute, non-oxidizing acid cona4. UUIVII'UDI luwo,

tainin a small amount of a sulphurized cinchona ark alkaloid.

2. A cleanin and pickling bath for metals comprising a ute, non-oxidizing acid con- 5 taining a small amount of sulphurized quinoidine.

3. In a process of cleaning and pickling metal articles, the step which comprises treating said articles with a dilute, non-oxidizing acid containing a sulphurized cinchona bark alkaloid. TIE a process of cleaning and pickling metal articles, the step which comprises treating said articles with a dilute, non-oxidizing acid containing a small amount of sulphurized quinoidine.

In testimony whereof, I affix my si ature.

GEORGE L 

